Unexpected Fantasy
by AssbuttInTheImpala
Summary: One Shot where Dean is sixteen years old and wants to get with his older brother's best friend Castiel Novak


**A/N So yeah I switched around their ages so that Sam is the older brother. It's an AU so I can do what I want :P **

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Sixteen year old Dean Winchester sits at his desk, which is conveniently placed so that his back is to the door, while his Twenty year old brother and his best friend sit downstairs and watch some nerdy ass movie. With one headphone in his ear that projects pornographic moans into his ear while on the computer screen in front of him is showing some gay porn video that he's not even interested in, his hand flies over his dick. He doesn't need the images to get off, his imagination does that for him but the sound of the video is just that much better with his fantasy.

It's then that he hears a creek of the wooden floorboards outside the room and he quickly positions himself so his body is hiding the screen of his computer. He slowly turns his head to look over to the door to see his brother's friend Castiel Novak walk through it. Dean skilfully tucks himself away and tries not to bring attention to the computer as he closes the window browser. Any suspicions that Castiel had he didn't show as he moves further into the joint bedroom that Dean shares with his brother to collect something from Sam's desk that is far enough away from Dean's that Castiel _shouldn't _see anything (in particular the raging hard on he's still supporting in his pants). They don't say anything to each other so Dean thinks he's in the clear and as soon as Castiel has left, Dean lets out a sigh of relief but now he's too nervous to continue with his endeavours and instead resumes working on the homework he has due tomorrow because if he doesn't, Sam's going to kick his ass to next Sunday.

Sam has always looked after Dean but Sam is naturally a genius unlike Dean. Dean's better with his hands and hates doing his school work but Sam insists on it and Dean wants to make Sam proud and not let him down by flunking out of high school. He's always had a strong pressure on his shoulders as he follows his genius brother (who goes to fucking Stanford) through school only four years behind meaning the older Winchester is still fresh in his teachers' minds. The teachers all have a high expectations thinking Dean would be just like Sam and would be just as smart and are always disappointed that Dean doesn't excel in the subjects. He hates it and he hates school. If he had it his way, he would drop out tomorrow but that would mean he'd have to put up with a disappointed Sam and Dean doesn't think he can handle that.

Finally, Dean finishes his homework. He checks it over a couple of times searching for any obvious errors before picking it up off the desk and standing from his chair to head downstairs. The perk of having a genius for a brother means he has a homework checker on hand and because Sam wants Dean to do well, he's always happy to help. Unfortunately, going downstairs would mean having to be in the same room as Castiel again and Dean doesn't think he can handle that.

Castiel has been Sam's best friend since they were in grade school and therefore Dean has known him practically his whole life. Dean watched from afar as the friends played in the backyard always being told that they were playing big boy games and Dean was too little but as soon as he hit the tender age of seven, they had let him join in. It was when Dean hit ten that he noticed how beautiful Castiel was. Dean had known always known that he was gay. He was always checking out the guys discreetly in the locker room and never once had a second glance at the girls in school. It was around the time of puberty that his view of Castiel being 'beautiful' evolved into 'sexy', 'gorgeous' and 'downright fuckable'. Of course Dean would always see Castiel as beautiful but the urge to be laid flat and fucked into hard by the older boy was always in the back of his mind when he saw him.

These thoughts lead Dean to be sufficiently awkward around the other boy, now man, and with the added embarrassment of being caught jacking off, even if Castiel _hadn't _seen anything, he doesn't think he will be able to survive the time that it will take Sam to read over his homework. Instead, he turns on his heel and heads back to their joint bedroom where he places his homework on the desk. He pulls out his phone and brings up a blank message to send to Sam telling him he left his homework on Sam's desk to check over for him because he's too tired to head downstairs.

When his phone shows confirmation that the message was sent, Dean heads to the bathroom and gets himself ready for bed. He'll deal with how horny he is in the shower tomorrow morning he thinks as he heads to bed.

Their joint bedroom is quite a big room that could quite easily be two decent sized rooms if they put a wall down the middle but they never had time or the money to do it and the boys had loved it when they were younger so it became the norm. Both the brothers had queen sized beds meaning whenever Castiel stayed over, he just slept in Sam's bed. Dean never minded that Castiel slept in the same room but now Dean wished he didn't.

Fortunately for Dean, just like his desk, his bed is positioned far away from Sam's so he can feign sleep once the friends enter the room. Luckily, Dean doesn't have to pretend because as soon as his head hits the pillow, Dean is out to the world and doesn't awaken until a hand is shaking his shoulder.

His eyes open groggily and his hands rise to his eyes to rub the sleep so he can see the time. The bright red illuminated numbers say 3:54am and Dean groans as he rolls over to see why he's been woken up. To his surprise, he finds none other than Castiel perched on the side of his bed staring down at Dean with wide eyes. He's about to speak but is stopped when Castiel raises his finger to Dean's lips and nods over to Sam's bed. Dean follows the head inclination and sees that Sam is still fast asleep.

That's when the confusion sinks in. Why is Castiel waking him up in the middle of the night and is currently sitting on the edge of his bed in nothing but boxer briefs and sporting a boner. Wait what? Dean has a double take looking up from Castiel's groin to his face only to look down again. He swallows the lump that had risen in his throat as he returns to look at Castiel in the eye. Dean is utterly confused by this turn of events and it must show on his face because suddenly Castiel is under the covers lying down next to him and is up in his personal space to whisper in his ear.

"You were masturbating when I walked in earlier weren't you?" Castiel asks his voice low and gravelly and it does wonders to Dean's erection he's been sporting since he noticed Castiel's. All Dean can do is nod as his teeth dig into his bottom lip holding back the whimper that threatens to escape. "What were you thinking about?" Castiel asks "Were you thinking about me, Dean?" the sound of Dean's name coming from Castiel in his low gravelly tone lets a whimper fall past Dean's lips. "I see you looking at me, Dean" Castiel continues "Always looking at me like you want my cock but as soon as I look at you, you're a blushing virgin" Castiel groans then "Are you a virgin, Dean?"

All Dean can do is nod because it's all true. He's always looking at Castiel when he's not looking and hoping that one day the older boy will notice Dean and not see him as his friend's little brother and someone he could potentially fuck into the mattress but of course, Dean would never get what he wants because in Castiel's eyes, Dean is just the annoying companion that comes in tow with Sam. But now, with what Castiel is whispering, Dean isn't so sure. He thought he had been careful, only sneaking glances when Castiel is pre-occupied but apparently he hasn't been and Castiel has noticed.

"Are you Dean?" Castiel asks again snapping Dean out of his inner monologue and Dean has to think for a moment trying to remember what Castiel is asking but then he remembers and he has to nod. It's true he's a virgin, he never had the chance to do anything more knowing that being gay is taboo in high school and everyone will treat you differently. He didn't want to risk the insults and the bullying so instead he just jacks off to fantasies in his bedroom hoping that Castiel would notice him one day and bring him out of his misery.

"Fuck" Castiel groans in Dean's ear "Do you have any idea what you do to me, Dean?" Castiel leans in now so close to Dean's ear that he can feel Castiel's lips brushing the skin "I've been waiting so fucking long, Dean. Always been the sweet little innocent baby brother to my best friend and totally off limits but you make it so fucking _hard_." Castiel growls as he grinds his dick into Dean's thigh and he can feel the length of it clearly through the two layers of thin boxers that they are both wearing. "But when I see you jacking your dick to gay porn, I know you want it. Tell me how bad you want it Dean" and the way Castiel says Dean's name has a drop of pre-come pearling at the tip and soaking his further.

"I want your dick, Cas" Dean whispers and the groan that Castiel lets out is more than enough encouragement that he said the right thing. "Please Cas. I need it so bad. It's all I think about and I just-" Dean's cut off from finishing the rest of his sentence as Castiel's lips are on his and there's a tongue exploring Dean's mouth and Dean is just so surprised by the turn of events that he can't do anything but let Castiel do as he please.

Without parting their lips, Castiel moves himself so that he's on top of Dean and he grinds himself down onto Dean's erection. The motion has Dean seeing stars and if it weren't for Castiel's mouth on his, he's sure the moan he would have let out would have woken Sam. He's so distracted by the tongue in his mouth and the teeth biting at his lips as well as the hips gyrating against his that he doesn't notice that Castiel's hands are removing Dean's boxers until his erection slaps against his stomach. The release has Dean gasping for air as his painfully hard erection is freed and then suddenly Castiel's mouth is gone from his and is engulfing his dick.

"Jesus Christ" Dean groans probably too loud given his brother is sleeping literally just across the room but his brother doesn't wake and Castiel's tongue is working miracles on his dick. His mouth practically swallows him down whole and Dean can feel his head pressed against the back of Castiel's throat before it slides deeper and now Dean is actually lodged in Castiel's throat and it's all he can do to hold back the sounds that beg to escape. His hands clench in the sheets and his hips threaten to buck up but Castiel's hands are firm and pin him to the mattress. Then Castiel swallows and Dean can't take it anymore. He has been on edge ever since his session earlier had been interrupted and he can't hold back. He shoots his load down Castiel's throat with a silent scream and Castiel just swallows everything that Dean has to offer.

Castiel's tongue gently licks him clean before he makes his way back up Dean's body and his tongue is once again in Dean's mouth but he has no energy to return the urgency that Castiel has. He's pliant under his touch too utterly blissed out to do anything but let the man have his way with him. He can taste himself on Castiel's tongue and he should be grossed out but he finds it strangely erotic and can't help but wonder what Castiel would taste like in his mouth. The thought has his spent cock twitching and he can feel the blood once again heading south as it starts to harden even though he only came minutes earlier. He knows if they're caught they're going to be in a boat load of trouble but that thought is pushed to the back of his mind as Castiel grinds his still hard dick into Dean's hip.

"Cas, please" He whimpers between kisses. Castiel pulls back and Dean can finally see those lust blown blue eyes with their pupils so wide that there is only a ring of blue at the edge of the iris.

"Beg me baby" Castiel taunts as he moves to Dean's neck and starts to suck. Dean bares his neck in submission and gives Castiel more access. He wants Castiel's marks on his body as a reminder of what happened so that in the morning, he knows it's real. That Castiel had his way with him.

"Please Cas, I need it. Please fuck me" Dean tries to plead through his pants. His erection is hard and heavy between his legs again already from the ministrations Castiel is performing on his body and he really just wants Castiel to get to the main event. "I want you inside me. Please Cas, fill me up"

Castiel groans in Dean's ear in response before he's reaching across the bed to Dean's bedside table to reach into the drawers where Dean hides his lube. He's not sure _how _Castiel knows it's there but Dean doesn't dare ask because that would mean that he would stop what he's doing and Dean is too desperate for Castiel to be inside him that he _really _doesn't want him to stop. There's a click as the lube is opened and Dean's breathing comes short and he's already clenching in anticipation. He's played with himself _down there _before but only a handful of times and only when he has the house to himself. He hasn't come out to his family and he really doesn't want to be caught with his pants down and his fingers in his ass because that would be all types of awkward.

"Just relax for me baby" Castiel purrs into Dean's ear and it's enough to calm him slightly but when the first touch of a cold slick finger brushes over his balls and then dives backwards to brush over his entrance, Dean's breath hitches and he's not sure he can do this. Nerves drive through him and he's about to back out the words are on the tip of his tongue but then Castiel is in his ear again. "You're so fucking perfect Dean. I've always wanted you. Do you know how fucking _beautiful _you are?" Castiel's eyes search Dean's as his finger continues to rub over his hole. "You don't do you? You're so incredible and you're all _mine_" he growls as he buries his head back into Dean's neck and sucks another mark. "Say it for me baby. Tell me you're mine" Castiel almost whines and Dean can hear the desperation in his voice. Castiel wants this as bad as Dean does and Dean knows if he told him to stop, he would. There's no doubt about it and Dean realises then that he wants this. They both do. This isn't a one off fuck and then they never talk about it again. This is the start of something more.

"Yours" he pants. "I'm all yours Cas"

Castiel's smile is predatory and hungry as he looks down at Dean but he can see the caring look in his eyes that confirms his earlier thoughts. This is something more. Once again, Dean is breathless as the finger that had been slowly making circles over Dean's entrance slides inside before it slips out only to dart back in again. It's slow and careful as Castiel's lips find Dean's again and their kiss is just as slow and more sensual than all their previous kisses and Dean wants to cry. Not because it hurts but because this is _Cas;_ the only person other than Sam who has always been there for him. He's the one who would always ask him to join in on their games when Sam had already told Dean to go away or would give Dean his slice of pie because he knows how much Dean loves pie. He doesn't realise he's actually crying until Castiel stops and looks at him. Really looks at him and then Castiel's face breaks and his finger is gone and Dean whines in protest.

"What's wrong? Do you want me to stop" he whispers and it's so caring that Dean can't do anything but laugh which just confuses the man hovering over him even more. He's never been good at words so instead, Dean removes his hand from where it was still clenched in the bed sheet and wraps it behind Castiel's neck where it tangles in his thick locks and pulls him down for a kiss.

"Don't stop" he pants when they part "It's perfect" he breathes across Castiel's lips and even though the man is still confused, his finger is inside him once again and Dean has had enough with the slow searching finger so he fucks his hips down onto the finger inside him. "More" he breathes and Castiel complies almost immediately as he kisses Dean's chest and sucks more and more marks into his skin. Dean knows he's going to be naked in front of the mirror in the days that follow pressing his fingers to the marks revelling in the burn that the touch will bring. He hopes that whatever is happening now – even with the worry of being discovered hovering over them – won't stop and the marks that Castiel leaves will never disappear.

Two fingers are stretching and scissoring him wide and Dean's hips are rocking down to meet them on every thrust. A third joins them and Dean lets out a moan that causes Castiel to put a hand over his mouth and stop his movement of his fingers. Castiel's head whips around to look over to Sam's bed but his brother is still asleep and the noise wasn't enough to wake him. Castiel hand slips away and he looks down at Dean with annoyed eyes before he places on finger to Dean's lips.

"You need to be quiet baby" he whispers and Dean just nods in reply. He knows they can't be discovered. Not like this anyway. Dean doesn't want to hide how he feels especially now that he knows Castiel feels the same way but there's a time and a place to think about that and with three fingers in his ass and a gorgeous man on top of him is not that time. Slowly, Castiel's fingers start to move again and Dean feels the burn of them stretching him and the pain causes tears to brim in the corners of his eyes but then Castiel is kissing them away and whispering sweet nothings in his ear. "You're doing so well baby. So perfect for me. Just relax baby. So perfect. So beautiful" Then the pain is just something that is bearable and no longer a barrier. Castiel's fingers are sliding in and out with ease and Dean's hips are once again rocking down onto the digits while his hands find purchase on Castiel's strong back and hold him close. Then the fingers are gone and Dean can feel his hole clench unconsciously at the emptiness and he wants the feeling back.

Dean watches as Castiel pulls away enough so that he can slick himself up with the lube. Dean bites his lips as he finally lays eyes on Castiel's cock and he's not ashamed that he actually drools. He has spent so long fantasising about it that now that it's finally in front of him, he can't believe how perfect it is and so much better than he imagined. It's so much larger than his own and as he watches it disappear into Castiel's fist, he lets out a whimper that catches Castiel's attention. The man smirks down at him before he once again covers Dean's body with his own and captures Dean's lips again. It's slow and searching as if they both have all the time in the world. Dean's hands tangle in Castiel's hair while Castiel's own move to Dean's thighs to press them up to Dean's chest. He pulls back again and Dean lifts his head to follow Castiel's lips which earns a small chuckle from Castiel and Dean can feel the vibrations in his chest. But then Castiel takes himself in hand again and is lining his head with Dean's hole. Dean gaps as just the head starts to breach and his whole body tenses. He knows he's supposed to relax but he can't. Not with the pain that he knows is to come but once again Castiel is in his ear as if the man can read Dean's mind and knows exactly what is going on.

"Dean, baby you need to relax. I don't want to hurt you" he's kissing at Dean's ear and running a hand through his hair which always relaxes him but his mind is so distracted by the cock that is about to breach his ass that he just can't. It could be hours, he doesn't know, but finally, he calms down because this is Cas and he's not going to hurt him. Castiel feels Dean's body relax and he coos into Dean's ear his praise "That's it baby. Tell if I'm hurting you and I'll stop" Dean nods in reply but he knows he won't back out now. Not now that they've come this far already. Dean wants to enjoy this. Then Castiel is sliding inside and the pain is too much and Dean cries out only to have it swallowed by Castiel's mouth. Once again, their tongues are tangling and Castiel's distraction is working because the pain is no more than a dull thud now. Dean can tell the man above him is holding back and there's a pang in his chest that this man cares so much for him that he's not taking what his body so desperately wants so that he can make it good for Dean.

Once again, Castiel does the inside Dean's head thing and he slowly starts to slide inside further and further, inch by inch, until he can't go any further and Dean's face is scrunched in pain at the foreign feeling of having a dick inside his ass but he's slowly adjusting to it and he can feel the pleasure starting to surface. He can feel Castiel throbbing inside him and he feels so deliciously full that he can't help but moan. Castiel looks down at Dean and smirks before his hips move back and his dick slides out almost all the way back before he's fucking back in again. The momentum of his thrust sends Dean up the bed slightly and he has to grip on tightly round Castiel's back to stop himself moving too much because he wants Castiel as deep inside him as he can get. He wraps his legs around Castiel's hips and pushes his heels into his ass to drive him deeper as Castiel fucks his hips back and forth.

Each thrust sends the air out of Dean and he's gasping to find it as Castiel's speeds up his hips and grunts Dean's name each time he snaps forward. It's so erotic that Dean can't believe it's actually happening and isn't something out of the pornos he's been watching but if this is a dream, he never wants to wake up because Castiel is in his arms and is thrusting forward into him and it's perfect. Then Castiel changes the angle and Dean cries out a strangled "Cas" as Castiel covers his mouth once again with his own to cover the sound. All thoughts of his brother in the bed just across the room are pushed from his mind as he gets lost in the pleasure of Castiel's dick in his ass. His own dick is sandwiched between their bodies and is sliding around as Castiel moves lubricated by the sweat and pre-come between them. It's all too much, and it's going to be over far too soon for Dean's liking but he can feel the familiar feeling pool in his gut and he gasps out to Castiel to warn him "I'm gonna come Cas" he squeaks.

"Come for me baby" Castiel growls as he wedges a hand between them and strokes Dean's dick. Dean thinks he probably could have come untouched but with Castiel's hand on him, it's all over. Dean's head throws back into the pillows as he comes between them in thick spurts of warm cum that mixes with the sweat they've produced and is mashed between their chests. He's not sure if he was quiet or not but he's not in the mood to care. He's too utterly blissed and relaxed to worry if he's woken his brother up or not. When he comes to, Castiel is still thrusting his hips into Dean's relaxed body and his head is buried in Dean's neck where he's grunting as he searches for his own release.

Dean's hands find their way to Castiel's sweaty hair where he cradles his head and pushes his hands through the thick strands. "Let go for me baby" Dean whispers "Come in my ass. Want to feel it" It's all Castiel needs before his biting down on Dean's collarbone to keep quiet as he's thrown into orgasm. Dean comforts him through it as he cards his hands through Castiel's hair. When Castiel's hips finally stop moving, he lays there panting onto Dean's chest. Dean's hand doesn't stop moving until Castiel's breathing finally evens out and he slips himself out of Dean's body. He raises himself up on his hands so he can hover over Dean's body. He leans down and kisses Dean once again and it's so lazy that their tongues are barely moving as they tangle together.

When they finally pull apart, they both break out in laughter. Dean can't believe that his fantasy actually came true. Castiel just fucked him into the mattress and all while his own brother was in the bed just across the room. The realisation that they haven't exactly been quiet for the past five minutes sends Dean into a panic and Castiel sees it before he once again whips his head around to see if Sam is still asleep. Dean props his head up to see for himself and once he has confirmation that is brother is still out to it, he flops back down and pushes Castiel's shoulder till he's lying on his back. Dean slinks to his side and lays his head down on the older boy's chest before he lets out a deep sigh. Castiel's hand is in his hair before it slides down to his shoulder and he pulls him closer in. Dean feels a light kiss pressed into his head.

"Cas," he whispers "Stay. I don't care what Sammy thinks"

"Of course" Castiel replies "We'll deal with it together"

Dean smiles into Castiel's chest and presses a small kiss to the skin. He's so happy that they're on the same page that everything he thought was true and Castiel wants more than just a one off thing. He wants Dean for the long hall and even if they have to go through hell to be together, they were going to do it. Together.

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**A/N Leave a review if you feel inclined :P Also I've set up a sideblog on Tumblr especially for my fanfiction stuff which is under 'assbuttintheimpalafiction' feel free to follow me on there and ask me stuff :) I'm currently writing another multi-chapter fic which I'm slowly writing still not sure when I'll publish it but I will publish it I promise :D**


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